1. Field of the Invention
The present invention relates to a data write circuit.
2. Description of the Related Art
For example, displaying an image, by using a computer, on an image display unit such as a display is performed by reading data written on a memory such as an image memory and generating image signals corresponding to the data. Writing the data into the memory is performed by a data write circuit capable of executing such processing. The data write circuit receives image data outputted from a central processing unit (CPU) and writes, into the memory, data corresponding to pixel data included in the image data. See, for example, Japanese Patent Application Laid-open Publication No. 2001-34258.
When rendering a pattern on an image display unit for example, there are quite a few occasions when a pattern is rendered which is obtained only by altering one or some of constituent parts of a master pattern. For example, each of patterns shown in FIGS. 22A to 22C can be understood to be rendered from a pattern shown in FIG. 21, which is made to be an original pattern, by omitting one of constituent parts thereof or changing one of display colors thereof. Many of patterns which can be understood as such patterns are capable of being rendered by utilizing image data of their original patterns.
In a conventional data write circuit, however, even when an image can be rendered by utilizing data of an original pattern as described above, a CPU side must prepare all of image data corresponding to the image which is to be newly rendered. Therefore, it could hardly be that the processing of writing data into a memory by the data write circuit was always efficiently performed.